A study to evaluate two approaches to the prevention of gingivitis in teenage children was begun in York County, Virginia in April 1987. Baseline examinations for periodontal health, DMFS and gingival recession were conducted on 500 ninth and tenth graders. Questionnaires regarding oral hygiene methods and professional care practices were completed. Following the examinations, subjects were randomly assigned by grade to either a positive control or test group. The control group received a manual for the self-assessment and control of plaque and the test group received a manual for the self-assessment and control of gingival bleeding. Small group and individual sessions for instruction in the self-assessment procedures were held to ensure that all procedures were understood. Interim examinations to assess periodontal health were conducted in October, 1987 and in April and October, 1988. In May, 1988 each participant was given the opportunity to have an oral prophylaxis and all participants received individual instruction to reinforce the appropriate group methods. Assessments for DMFS and gingival recession were included along with the periodontal assessments on the final examination, conducted in April, 1989. Following data analysis, final reports will be prepared.